Thin film magnetic head structure, method of making the same and thin film magnetic head

ABSTRACT

A thin-film magnetic head structure has a configuration adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated. The main magnetic pole layer has an end face joint structure where respective end faces of the magnetic pole end part and a yoke magnetic pole part having a size greater than that of the magnetic pole end part are joined to each other, and a surface with a flat structure on a side closer to the thin-film coil.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thin-film magnetic head structure for manufacturing a thin-film magnetic head which performs magnetic recording operations by perpendicular recording, a method of manufacturing the same, and a thin-film magnetic head.

2. Related Background Art

In recent years, the areal density in hard disk drives has been increasing remarkably. Recently, the areal density in hard disk drives has reached 160 to 200 GB/platter in particular, and is about to increase further. Accordingly, thin-film magnetic heads have been required to improve their performances.

In terms of recording schemes, thin-film magnetic heads can roughly be divided into those for longitudinal recording in which information is recorded in a (longitudinal) direction of a recording surface of a hard disk (recording medium) and those for perpendicular recording in which data is recorded while the direction of recording magnetization formed in the hard disk is perpendicular to the recording surface. As compared with the thin-film magnetic heads for longitudinal recording, the thin-film magnetic heads for perpendicular recording have been considered more hopeful, since they can realize a much higher recording density while their recorded hard disks are less susceptible to thermal fluctuations.

Conventional thin-film magnetic heads for perpendicular recording are disclosed, for example, in U.S. Pat. No. 6,504,675, U.S. Pat. No. 4,656,546, U.S. Pat. No. 4,672,493, and Japanese Patent Application Laid-Open No. 2004-94997.

Meanwhile, when thin-film magnetic heads for perpendicular recording record data onto areas in inner and outer peripheries of a hard disk, a magnetic pole end part disposed on the side of a medium-opposing surface (also referred to as air bearing surface, ABS) opposing the recording medium (hard disk) yields a certain skew angle with respect to a data recording track. In perpendicular magnetic recording heads (hereinafter also referred to as “PMR”) having a high writing capability, the skew angle has caused a problem of so-called side fringe in which unnecessary data are recorded between adjacent tracks. The side fringe adversely affects the detection of servo signals and the S/N ratio of reproduced waveforms. Therefore, in conventional PMRs, the magnetic pole end part on the ABS side in the main magnetic pole layer has a bevel form gradually narrowing in width toward one direction (see, for example, Japanese Patent Application Laid-Open Nos. 2003-242607 and 2003-203311 in this regard).

SUMMARY OF THE INVENTION

However, the conventional PMRs have been problematic in that they cause a phenomenon known as pole erasure by which data recorded beforehand on a hard disk is erased when information is further recorded at a high density. The pole erasure is a phenomenon in which, after data is written on a recording medium (hard disk) having a high maximum coercivity Hc, a leakage magnetic flux flows from the ABS to the hard disk even when no write current flows through a thin-film coil, thereby erasing the other data.

This point will be explained in further detail.

An example of the conventional PMRs is a thin-film magnetic head 400 having a structure shown in FIGS. 27(A), (B), and (C). This thin-film magnetic head 400 includes a main magnetic pole layer 402 which is formed on an insulating layer 401 and has a bevel-shaped magnetic pole end part disposed on the side of an ABS 403; a write shield layer 405 which is magnetically connected to the main magnetic pole layer 402 and opposes the main magnetic pole layer 402 by way of a recording gap layer 404 on the ABS 403 side; and a thin-film coil 406. The thin-film coil 406 is wound in a planar spiral about a junction 408 connecting the main magnetic pole layer 402 and the write shield layer 405, while its windings are insulated from each other by a photoresist 407.

In the conventional PMRs, as in the thin-film magnetic head 400, a magnetic material is magnetized such that the direction of magnetization ms is oriented so as to extend along the ABS 403, whereby the main magnetic pole layer 402 is formed.

In the conventional PMRs such as the thin-film magnetic head 400, however, even when the direction of magnetization ms is oriented so as to extend along the ABS 403, the direction of remnant magnetization mr inside the main magnetic pole layer 402 after completion of writing is oriented toward the ABS 403 side and thus faces a different direction than the magnetization ms. (The direction different from that extending along the ABS will be referred to as “different direction” in the following.) Therefore, when such a PMR writes data, leakage magnetic fluxes due to the remnant magnetization mr may erase data already written on a hard disk or weaken signals of written data even though no write current is flowing.

In order to overcome the problem mentioned above, it is an object of the present invention to provide a thin-film magnetic head structure which can manufacture a thin-film magnetic head comprising a structure capable of preventing the pole erasure from occurring while improving the recording density, a method of manufacturing the same, and a thin-film magnetic head.

For solving the above-mentioned problem, in one aspect, the present invention provides a thin-film magnetic head structure adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated; wherein the main magnetic pole layer has an end face joint structure where respective end faces of the magnetic pole end part and a yoke magnetic pole part having a size greater than that of the magnetic pole end part are joined to each other, and a surface with a flat structure on a side closer to the thin-film coil.

In this thin-film magnetic head structure, the end face joint between the magnetic pole end part and the yoke magnetic pole part blocks the emission of remnant magnetization from the yoke magnetic pole part to the magnetic pole end part.

It will be preferred if the thin-film magnetic head structure further comprises a base insulating layer including a magnetic pole forming depression sunken into a form corresponding to the main magnetic pole layer, the magnetic pole forming depression having a very narrow groove part formed so as to define a track width of the thin-film magnetic head, whereas the respective end faces of the magnetic pole end part and yoke magnetic pole part are joined to each other within a region other than the very narrow groove part in the magnetic pole forming depression of the base insulating layer.

In this case, the main magnetic pole layer is formed so as to be embedded in the magnetic pole forming depression.

It will be preferred in the thin-film magnetic head structure if the magnetic pole end part and the yoke magnetic pole part are formed from respective magnetic materials having saturated magnetic flux densities different from each other. It will also be preferred if the saturated magnetic flux density of the magnetic pole end part is set higher than the saturated magnetic flux density of the yoke magnetic pole part.

The magnetic pole end part and the yoke magnetic pole part may be joined to each other by way of a nonmagnetic film made of a nonmagnetic material.

An upper yoke magnetic pole part having a size greater than that of the magnetic pole end part may be joined to a portion of the yoke magnetic pole part distant from the medium-opposing surface than the recording gap layer.

The very narrow groove part may be formed such that a groove width intersecting the length thereof gradually decreases along the depth thereof.

In another aspect, the present invention provides a method of manufacturing a thin-film magnetic head structure adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated; the method comprising the steps of:

(1) forming an end-face-equipped magnetic pole layer having an exposed end face at a position where the magnetic pole end part is to be formed;

(2) forming a joining magnetic pole layer joined to the exposed end face of the end-face-equipped magnetic pole layer at a position where a yoke magnetic pole part having a size greater than that of the magnetic pole end part is to be formed;

(3) surface-flattening the end-face-equipped magnetic pole layer and joining magnetic pole layer on the side closer to the thin-film coil, so as to form the magnetic pole end part and the yoke magnetic pole part having a size greater than that of the magnetic pole end part;

(4) forming the recording gap layer with the magnetic pole end part and the yoke magnetic pole part;

(5) forming the thin-film coil with the yoke magnetic pole part such that the thin-film coil and the yoke magnetic pole part are in contact with each other by way of an insulating layer; and

(6) forming the write shield layer such that the write shield layer opposes the magnetic pole end part by way of the recording gap layer.

In still another aspect, the present invention provides a method of manufacturing a thin-film magnetic head structure adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated; the method comprising the steps of:

(1) forming a base insulating layer including a magnetic pole forming depression sunken into a form corresponding to the main magnetic pole layer, the magnetic pole forming depression having a very narrow groove part formed so as to define a track width of the thin-film magnetic head;

(2) forming an end-face-equipped magnetic pole layer having an in-depression end face exposed into a region other than the very narrow groove part in the magnetic pole forming depression of the base insulating layer;

(3) forming a joining magnetic pole layer joined to the in-depression end face in the end-face-equipped magnetic pole layer;

(4) surface-flattening the end-face-equipped magnetic pole layer and joining magnetic pole layer on the side closer to the thin-film coil, so as to form the magnetic pole end part and the yoke magnetic pole part having a size greater than that of the magnetic pole end part;

(5) forming the recording gap layer with the magnetic pole end part and the yoke magnetic pole part;

(6) forming the thin-film coil with yoke magnetic pole part such that the thin-film coil and the yoke magnetic pole part are in contact with each other by way of an insulating layer; and

(7) forming the write shield layer such that the write shield layer opposes the magnetic pole end part by way of the recording gap layer.

The above-mentioned manufacturing methods may further comprise the step of forming a nonmagnetic film made of a nonmagnetic material at the exposed end face in the end-face-equipped magnetic pole layer, whereas the joining magnetic pole layer may be formed so as to join with the end-face-equipped magnetic pole layer by way of the nonmagnetic film.

The methods may further comprise the step of forming a nonmagnetic film made of a nonmagnetic material at the in-depression end face in the end-face-equipped magnetic pole layer, whereas the joining magnetic pole layer may be formed so as to join with the end-face-equipped magnetic pole layer by way of the nonmagnetic film.

The methods may further comprise the step of joining an upper yoke magnetic pole part having a size greater than that of the magnetic pole end part to a portion of the yoke magnetic pole part distant from the medium-opposing surface than the recording gap layer.

In still another aspect, the present invention provides a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated; the thin-film magnetic head comprising a base insulating layer including a magnetic pole forming depression sunken into a form corresponding to the main magnetic pole layer, the magnetic pole forming depression having a very narrow groove part formed so as to define a track width of the thin-film magnetic head; wherein the main magnetic pole layer has an end face joint structure where respective end faces of the magnetic pole end part and a yoke magnetic pole part having a size greater than that of the magnetic pole end part are joined to each other, and a surface with a flat structure on a side closer to the thin-film coil.

The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of the thin-film magnetic head structure in accordance with a first embodiment of the present invention, in which (A) is a sectional view taken along a direction intersecting a thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 2 is a view showing an insulating layer, in which (A) is a plan view, and (B) is a sectional view taken along the line B-B of (A);

FIG. 3 is a view showing a major part of FIG. 2 under magnification with changed ratios of dimensions, in which (A) is a plan view, (B) is a sectional view taken along the line B-B of (A), and (C) is a sectional view showing the major part in (B) under magnification;

FIG. 4 is a view showing a main magnetic pole layer after being cut along the ABS, in which (A) is a perspective view, and (B) is a sectional view taken along the line B-B of (A);

FIG. 5 is a plan view showing the main magnetic pole layer;

FIG. 6 is a view showing another main magnetic pole layer after being cut along the ABS, in which (A) is a perspective view, and (B) is a sectional view taken along the line B-B of (A);

FIG. 7 is a plan view or sectional view in a step of the manufacturing method in accordance with the first embodiment, in which (A) is a plan view, (B) is a sectional view taken along the line B-B of (A), (C) is a plan view showing a major part of (A) under magnification with changed ratios of dimensions, and (D) is a sectional view taken at the ABS in (B);

FIG. 8 is a plan view or sectional view in a step subsequent to FIG. 7, in which (A) is a plan view, (B) is a sectional view taken along the line B-B of (A), (C) is a plan view showing a major part of (A) under magnification with changed ratios of dimensions, and (D) is a sectional view taken at the ABS in (B);

FIG. 9 is a plan view or sectional view in a step subsequent to FIG. 8, in which (A) is a plan view, (B) is a sectional view taken along the line B-B of (A), (C) is a plan view showing a major part of (A) under magnification with changed ratios of dimensions, and (D) is a sectional view taken at the ABS in (B);

FIG. 10 is a plan view or sectional view in a step subsequent to FIG. 9, in which (A) is a plan view, (B) is a sectional view taken along the line B-B of (A), (C) is a plan view showing a major part of (A) under magnification with changed ratios of dimensions, and (D) is a sectional view taken at the ABS in (B);

FIG. 11 is a plan view or sectional view in a step subsequent to FIG. 10, in which (A) is a plan view, (B) is a sectional view taken along the line B-B of (A), (C) is a plan view showing a major part of (A) under magnification with changed ratios of dimensions, and (D) is a sectional view taken at the ABS in (B);

FIG. 12 is a sectional view in a step subsequent to FIG. 11, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 13 is a sectional view in a step subsequent to FIG. 12, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 14 is a sectional view in a step subsequent to FIG. 13, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 15 is a sectional view in a step subsequent to FIG. 14, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 16 is a sectional view of the thin-film magnetic head structure in accordance with a second embodiment of the present invention, in which (A) is a sectional view taken along a direction intersecting a thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 17 is a plan view or sectional view in a step of the manufacturing method in accordance with the second embodiment, in which (A) is a plan view, (B) is a sectional view taken along the line B-B of (A), (C) is a plan view showing a major part of (A) under magnification with changed ratios of dimensions, and (D) is a sectional view taken at the ABS in (B);

FIG. 18 is a sectional view in a step subsequent to FIG. 17, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 19 is a sectional view of the thin-film magnetic head structure in accordance with a modified example of the first embodiment, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 20 is a sectional view of the thin-film magnetic head structure in accordance with a modified example of the second embodiment, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 21 is a sectional view of the thin-film magnetic head structure in accordance with a third embodiment, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 22 is a sectional view of the thin-film magnetic head structure in accordance with a modified example of the third embodiment, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS;

FIG. 23 is a sectional view showing a conventional method of manufacturing a thin-film magnetic head, in which (A) and (B) illustrate respective states before and after etching;

FIG. 24 is a plan view showing the main magnetic pole layer in a conventional thin-film magnetic head, in which (A) illustrates the main magnetic pole layer as set, and (B) illustrates the main magnetic pole layer manufactured;

FIG. 25 is a sectional view showing a conventional method of manufacturing a thin-film magnetic head, in which (A) illustrates a state provided with a photoresist, and (B) illustrates a state after removing the photoresist;

FIG. 26 is a sectional view showing a conventional method of manufacturing a thin-film magnetic head, in which (A) illustrates a state provided with another photoresist, and (B) illustrates a state after removing the photoresist; and

FIG. 27 shows an example of conventional thin-film magnetic heads, in which (A) is a sectional view, (B) is a front view showing the ABS, and (C) is a plan view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention will be explained with reference to the drawings. Constituents identical to each other will be referred to with numerals identical to each other without repeating their overlapping descriptions.

First Embodiment

Configuration of Thin-Film Magnetic Head Structure

First, with reference to FIGS. 1 to 6, the configuration of the thin-film magnetic head structure in accordance with the first embodiment of the present invention will be explained. FIG. 1 is a sectional view of a thin-film magnetic head structure 300 in accordance with the first embodiment of the present invention, in which (A) is a sectional view taken along a direction intersecting a thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS.

The thin-film magnetic head structure 300 in accordance with the first embodiment has a configuration adapted to manufacture a magnetic head for perpendicular recording. The thin-film magnetic head structure 300 is formed on a substrate which is not depicted, and yields a thin-film magnetic head in the present invention when cut at an ABS 30 which is a medium-opposing surface opposing a recording medium (hard disk).

The thin-film magnetic head structure 300 comprises a substrate; a reproducing head structure, laminated on the substrate, for manufacturing a reproducing head comprising an MR device (magnetoresistive device) or the like; and a recording head structure for manufacturing a recording head. FIG. 1(A) and (B) show the recording head structure laminated on the insulating layer 1, while omitting the substrate and the reproducing head structure.

The configuration of a major part of the recording head structure in the thin-film magnetic head structure 300 will be explained in the following, whereas the configuration of the other parts will be explained in manufacturing steps which will be set forth later. Each constituent in the recording head structure will be explained with the same name and numeral before and after being cut at the ABS 30 unless otherwise specified in particular. When distinguishing these states from each other, however, “′” will be added to the numeral referring to the state after being cut at the ABS 30.

The thin-film magnetic head structure 300 comprises the insulating layer 1, and a main magnetic pole layer 10, a recording gap layer 24, a write shield layer 40, a back magnetic pole layer 51, and a thin-film coil 100 which are laminated on the insulating layer 1.

The insulating layer 1 is the base insulating layer in the present invention and is formed in a predetermined region on the substrate. FIG. 2 is a view showing the insulating layer 1, in which (A) is a plan view, and (B) is a sectional view taken along the line B-B of (A). FIG. 3 is a view showing a major part of FIG. 2, in which (A) is a plan view, (B) is a sectional view taken along the line B-B of (A), and (C) is a sectional view showing the major part in (B) under magnification with changed ratios of dimensions. In the insulating layer 1, FIG. 2 shows a rectangular predetermined region centered at a cavity 2 which will be explained later.

The insulating layer 1 is made of alumina (Al₂O₃) and has the cavity 2 at a center part (hatched part in FIGS. 2(A) and 3(A)) on the side of a surface to be formed with a recording head. The cavity 2 is the magnetic pole forming depression in the present invention, and is sunken into a form corresponding to the outer form of the main magnetic pole layer 10 in order to form the main magnetic pole layer 10 in set dimensions and shape. Namely, as will be explained later in detail, the cavity 2 is formed earlier than the main magnetic pole layer 10, such that its dimensions and shape including the depth d1 (about 0.25 to 0.35 μm, preferably 0.3 μm), width, and length coincide with assumed thickness, width, and length of the main magnetic pole layer 10. The cavity 2 includes a very narrow groove part 3, a variable width depression 4, a fixed width depression 5, and a protruded depression 6, whereas a magnetic material embedded therein forms the main magnetic pole layer 10.

The very narrow groove part 3 is formed so as to define the track width of the thin-film magnetic head, and has a structure adapted to improve the recording density by reducing the track width. As shown in FIG. 3, the length of the narrow groove 3 is set to L1 (longer than a neck height NH which will be explained later, i.e., L1>NH) such that the ABS 30 can be secured in an intermediate part of the length. The groove width intersecting the length is W3 on the surface side, and is W4 on the lower side, whereas the groove widths W3 and W4 are made narrower than the variable width depression 4 and fixed width depression as much as possible, so as to yield a very narrow structure in order to improve the recording density of the thin-film magnetic head. Also, the groove width gradually decreases along the depth such that a magnetic pole end part 11 which will be explained later has a bevel form. Namely, the groove width W4 is smaller than the groove width W3 (W3>W4) in the very narrow groove part 3, so that the bevel angle θ shown in (C) of FIG. 3 becomes about 7 to 12 degrees (e.g., 10 degrees).

The variable width depression 4, whose groove width gradually increases, is connected to the very narrow groove part 3. The distance from the boundary part between the variable width depression 4 and very narrow groove part 3 to the ABS 30 will later become the neck height NH. The fixed width depression 5 having a constant groove width is connected to the variable width depression 4. The protruded depression 6 is connected to the end part of the very narrow groove part 3 opposite from the variable width depression 4.

As shown in FIGS. 4 and 5, the main magnetic pole layer 10′ (as with the main magnetic pole layer 10 before cutting) comprises a magnetic pole end part 11′ and a yoke magnetic pole part 20′, whereas its surface on the side closer to the thin-film coil 100 has a stepless flat structure. FIG. 4 is a view showing the main magnetic pole layer 10′ after being cut along the ABS 30, in which (A) is a perspective view, and (B) is a sectional view taken along the line B-B of (A). FIG. 5 is a plan view showing the main magnetic pole layer 10′. The main magnetic pole layer 10′ is formed so as to be embedded in the cavity 2. The main magnetic pole layer 10′ has an end face joint structure in which respective end faces of the magnetic pole end part 11′ and yoke magnetic pole part 20′ extending along the ABS 30 are joined to each other in a region (variable width depression 4) other than the very narrow groove part 3 in the cavity 2. The joint of the end faces forms an interface 14.

The magnetic pole end part 11′ (as with the magnetic pole end part 11 before cutting) is disposed at a position closer to the ABS 30 than is the yoke magnetic pole part 20′. The magnetic pole end part 11′ comprises a track width defining part 12 having a constant width for defining the track width, and a variable width part 13 whose width extending along the ABS 30 gradually increases in the direction away from ABS 30. The magnetic pole end part 11′ has a length D2 from the ABS 30. The length D2 is shorter than the length D1 from the ABS 30 to the rear end part of the yoke magnetic pole part 20′, so as to yield a shortened structure in which the magnetic pole end part 11′ is not connected to the write shield layer 40.

In order to achieve a higher data recording density by the thin-film magnetic head, the magnetic pole end part 11 has a narrow track width structure in which a width W1 to be explained later is narrowed. However, the magnetic pole end part 11 uses a magnetic material (Hi-Bs material) having a saturated magnetic flux density higher than that of the yoke magnetic pole part 20 so as not to be saturated with magnetic fluxes even in the narrow track width structure. The magnetic pole end part 11 and yoke magnetic pole part 20 are magnetized such that the direction of magnetization ms aligns with the ABS 30 (see FIG. 5).

The track width defining part 12 has a width determined by the very narrow groove part 3. Along the ABS 30, the track width defining part 12 has a width W1 on the side closer to the thin-film coil 100, and a width W2 on the side farther from the thin-film coil 100, thereby yielding a bevel form whose width gradually decrease in the direction away from the thin-film coil 100 (W1>W2, whereas the width W1 is the track width). These widths W1 and W2 correspond to the groove widths W3 and W4 of the very narrow groove part 3 in the cavity 2, respectively.

The length of the track width defining part 12 (distance from the ABS 30) corresponds to the neck height NH (which is on the order of 0.1 to 0.3 μm, preferably 0.15 μm in this embodiment).

The variable width part 13 is integrally formed with the track width defining part 12 from the same magnetic material as that of the latter, while the length from the ABS 30 is made shorter so as not to be connected to the back magnetic layer 51. The end face extending along the ABS 30 in the variable width part 13 is a joining end face 11 a, which is connected to a joining end face 20 a of the yoke magnetic pole part 20′, which will be explained later. The joining end faces 11 a and 20 a form the interface 14. The interface 14 is substantially parallel to the ABS 30.

The yoke magnetic pole part 20′ has a size (area) greater than that of the magnetic pole end part 11′. The yoke magnetic pole part 20′ comprises a variable width region 21 whose width gradually increases in the direction away from the ABS 30, and a fixed width region 22 having a constant width. In the variable width region 21, the end face extending along the ABS 30 on the ABS 30 side is the joining end face 20 a. At a position distant from the ABS 30 than the recording gap layer 24, the fixed width region 22 is magnetically connected to the back magnetic pole layer 51.

By way of the recording gap layer 24 and an insulating layer 31, the thin-film coil 100 is formed so as to ride on the variable width region 21 and fixed width region 22 of the yoke magnetic pole part 20′.

Referring to FIG. 1 again, the recording gap layer 24 is formed between the main magnetic pole layer 10 and a first shield part 41 of the write shield layer 40, which will be explained later, and the insulating layer 31.

The write shield layer 40 comprises the first shield part 41, a second shield part 42, and a third shield part 43. The first shield part 41 is formed so as to oppose the magnetic pole end part 11 of the main magnetic pole layer 10 by way of the recording gap layer 24 on the ABS 30 side, whereby the neck height NH is determined by the distance from the ABS 30 in a direction intersecting the ABS 30.

The second shield part 42 is formed so as to connect with the first shield part 41 and back magnetic pole layer 51 from the side closer to the thin-film coil 100, and has a height equivalent to the thickness of the thin-film coil 100.

The third shield part 43 is formed so as to connect with the second shield part 42 and cover the thin-film coil 100 and a photoresist 101 by way of an insulating layer 32.

The back magnetic pole layer 51 is connected to the yoke magnetic pole part 20 in a part distant from the ABS 30 than the recording gap layer 24. The back magnetic pole layer 51 is magnetically connected to the second shield part 42, and forms a joint 44 together with the second shield part 42.

The thin-film coil 100 is wound in a planar spiral about the write shield layer 40 while being insulated therefrom by way of the insulating layers 31, 32. Though not depicted, the thin-film magnetic head 100 may be changed to a helical coil spirally wound about the main magnetic pole layer 10.

Thus configured thin-film magnetic head structure 300 is cut so as to form the ABS 30 in an intermediate part of the very narrow groove part 3, whereby a thin-film magnetic head 300A in accordance with the present invention (see FIG. 1) is obtained.

In conventional PMRs, as in the thin-film magnetic head 400 shown in FIG. 27, the main magnetic pole layer 402 is formed by the same magnetic material from the ABS 403 to the opposite end part by way of the thin-film coil. Therefore, the remnant magnetization mr is directed to the ABS 403, thus making it difficult to prevent the pole erasure from occurring.

In the thin-film magnetic head structure 300 in accordance with this embodiment, by contrast, the recording head structure includes the above-mentioned main magnetic pole layer 10, whereas the main magnetic pole layer 10 has an end face joint structure formed by two magnetic poles, i.e., the magnetic pole end part 11 and yoke magnetic pole part 20. As shown in FIG. 5, the interface 14 formed by the end face joint between the magnetic pole end part 11 and yoke magnetic pole part 20 blocks the emission of remnant magnetization mr₂₀ from the yoke magnetic pole part 20 to the magnetic pole end part 11. As a consequence, the thin-film magnetic head structure 300 can make a thin-film magnetic head with reduced remnant magnetization mr directed to the ABS 30. Therefore, using the thin-film magnetic head structure 300 can manufacture a thin-film magnetic head which can effectively prevent the pole erasure from occurring.

Since the magnetic pole end part 11 is made smaller than the yoke magnetic pole part 20, such that the yoke magnetic pole part 20 has a size (area) greater than that of the magnetic pole end part 11, the quantity of magnetization (also known as magnetic volume) of the yoke magnetic pole part 20 is greater than that of the magnetic pole end part 11. However, the interface 14 blocks the emission of remnant magnetization from the yoke magnetic pole part 20 having a greater quantity of magnetization, so that the emission of remnant magnetization decreases drastically, whereby the pole erasure is more effectively prevented from occurring. When the width of the very narrow groove part 3 is made as narrow as possible, the track width can be reduced, whereby the recording density can be improved. Therefore, the thin-film magnetic head structure 300 can manufacture a thin-film magnetic head which can effectively prevent the pole erasure from occurring, while improving the recording density.

Meanwhile, in the case of a conventional PMR, the main magnetic pole layer is preferably a magnetic material with a small maximum coercivity Hc (about 2-10 Oe) and a small magnetostriction λ (1-3×10⁻⁶), while it is also preferably a magnetic material with a small magnetostriction λ in order to eliminate the aforementioned pole erasure.

However, in order to avoid impairment in the overwrite characteristic which occurs with flux saturation even if the track width is narrowed to improve the recording density, the magnetic material of the main magnetic pole layer is preferably formed of a magnetic material with a high saturated flux density, but when this is done it becomes difficult to lower the magnetostriction λ of the main magnetic pole layer. In view of this point, the above-mentioned thin-film magnetic head structure 300 forms the main magnetic pole layer 10 as a joint structure made of the magnetic pole end part 11 and yoke magnetic pole part 20 having respective saturated magnetic flux densities different from each other, while the saturated magnetic flux density of the yoke magnetic pole part 20 is made lower than that of the magnetic pole end part 11, so as to reduce the magnetostriction λ of the yoke magnetic pole part 20. This makes the main magnetic pole layer 10 reduce the magnetostriction λ as a whole. Hence, using the thin-film magnetic head structure 300 yields a thin-film magnetic head which can more effectively prevent the pole erasure from occurring.

In addition, the thin-film magnetic head structure 300 includes the insulating layer 1 provided with the cavity 2 in which the main magnetic pole layer 10 is embedded, and thus exhibits the following operations and effects. The operations and effects of the thin-film magnetic head structure 300 and the thin-film magnetic head manufactured therefrom will now be explained in comparison with the conventional PMRs.

In order to for the ABS-side portion of the magnetic pole end part in the main magnetic pole layer to be formed like a bevel, the following procedure has been employed in conventional PMRs. Namely, in the conventional PMRs, there has been a case where, as shown in FIG. 23(A), a main magnetic pole layer 501 formed on an insulating layer 500 is formed with an insulating layer 502 made of alumina, and is subjected to ion beam etching (hereinafter referred to as “IBE”) by direct irradiation with ion beams P. In this case, the etching speed by the IBE is slower in the magnetic pole end part in the main magnetic pole layer 501 than in the insulating layer 500, whereby the IBE must be performed for a long time in order for the magnetic pole end part to attain a bevel form. As a consequence, the ABS-side portion of the magnetic pole end part tends to have a form including a narrowed part 501 a having a smaller diameter as shown in FIG. 23(B).

Therefore, even when the main magnetic pole layer 501 is intended to be formed as shown in FIG. 24(A), a narrow band part 501 b corresponding to the track width may retract as shown in FIG. 24(B), so as to yield a flare point, thereby making the neck height NH longer than its expected length (about 0.15 μm) by d (about 0.2 to 0.3 μm). Therefore, the conventional PMRs have been hard to increase the quantity of magnetization in places near the ABS 503, which makes it difficult to yield a favorable overwrite characteristic (a characteristic by which data recorded on a recording medium is overwritten with another data).

The magnetic pole end part in the main magnetic pole layer 501 has conventionally been formed by plating using photolithography. In order for the ABS-side portion to have a bevel form, a resist pattern 504 having a taper angle as shown in FIG. 25(A) may be used. When the track width is to be narrowed in order to improve the recording density in this case, the ion beams P must be emitted after removing the resist pattern 504 as shown in FIG. 25(B), so as to perform trimming with the IBE for a long time. This may make the track width unfavorable or deteriorate the yield.

On the other hand, it has been quite difficult to perform plating while using a narrow resist pattern, thus leaving a fear of the formed magnetic pole end part falling down because of the IBE as shown in FIGS. 26(A) and (B).

Thus, the conventional PMRs have also been problematic in that the main magnetic pole layer becomes harder to form reliably when the recording density is to be improved.

By contrast, the thin-film magnetic head structure 300 in this embodiment includes the insulating layer 1 provided with the cavity 2, in which the main magnetic pole layer 10 is embedded, and thus can eliminate all of the foregoing problems.

Namely, since the cavity 2 is sunken into a form corresponding to the outer form of the main magnetic pole layer 10, the main magnetic pole layer 10 can be formed in the shape and dimensions as set when formed so as to be embedded into the cavity 2. Since the track width is determined by the very narrow groove part 3 of the cavity 2, there is no need to perform the IBE for a long time at all in order for the magnetic pole end part to have a bevel form. Therefore, the neck height can be set to a value as assumed, the quantity of magnetism in places near the ABS 403 can be enhanced, and a thin-film magnetic head having a favorable overwrite characteristic can be manufactured.

The track width can be narrowed if the width of the very narrow groove part 3 is reduced as much as possible, whereas the very narrow groove part 3 can set the track width to a value assumed. Therefore, not only the track width is narrow, but also the dimensional accuracy and yield become favorable, and there is no fear of the formed magnetic pole end part falling down. Therefore, providing the cavity 2 as in the thin-film magnetic head structure 300 can reliably form the main magnetic pole layer having an enhanced recording density.

MODIFIED EXAMPLE 1

The above-mentioned thin-film magnetic head structure 300 includes the main magnetic pole layer 10 in which the interface 14 is formed substantially parallel to the ABS 30. However, the thin-film magnetic head structure 300 may have a main magnetic pole layer 15 as shown in FIG. 6. Unlike the interface 14, the interface 17 in the main magnetic pole layer 15 is tilted by a fixed inclined angle with respect to the ABS 30. The same operations and effects as those of the above-mentioned thin-film magnetic head structure 300 and the thin-film magnetic head 300A manufactured therefrom are exhibited in this case as well.

MODIFIED EXAMPLE 2

In the above-mentioned thin-film magnetic head structure 300, the insulating layer 1 includes the cavity 2 within which the magnetic pole end part 11 and the yoke magnetic pole part 20 are joined to each other. However, the thin-film magnetic head structure in the present invention may be a thin-film magnetic head structure 302 (see FIG. 1) using no cavity as well. The thin-film magnetic head structure 302 has the same cross-sectional structure as with the thin-film magnetic head structure 300 shown in FIG. 1, and includes an end face joint structure in which respective end faces of the magnetic pole end part 11 and the yoke magnetic pole part 20 are joined to each other, whereas the surface on the side closer to the thin-film coil 100 has a flat structure. Therefore, the thin-film magnetic head structure 302 can also manufacture a thin-film magnetic head adapted to effectively prevent the pole erasure from occurring, while improving the recording density.

Method of Manufacturing Thin-Film Magnetic Head Structure

With reference to FIGS. 1, 2(A) and (B), and 3(A), (B), and (C) mentioned above and FIGS. 7(A), (B), (C), and (D) to 11(A), (B), (C), and (D), and 12(A) and (B) to 15(A) and (B), a method of manufacturing the thin-film magnetic head structure 300 having the above-mentioned configuration in accordance with the first embodiment will be explained.

FIGS. 7 to 15 are plan or sectional views in respective steps of the manufacturing method, in which (A) is a plan view, and (B) is a sectional view taken along the line B-B of (A). (C) is a plan view showing a major part of (A) under magnification, and (D) is a sectional view taken at the ABS 30 of (B). For convenience of illustration, (C) in each drawing shows the major part of (A) under magnification with a changed ratio of dimensions.

First, in the manufacturing method in accordance with this embodiment, a reproducing head structure comprising an MR device (magnetoresistive device) and the like is laminated on an undepicted substrate made of aluminum oxide titanium carbide (Al₂O₃.TiC), for example. Subsequently, an insulating layer 1 is formed from alumina (Al₂O₃) or a nonmagnetic material.

After a photoresist is applied onto the insulating layer 1, patterning is performed with a predetermined photomask, so as to yield a resist pattern exposing the surface of the insulating layer 1 into a form corresponding to the cavity 2. Using this resist pattern as a mask, reactive ion etching (hereinafter referred to as “RIE”) is carried out, so as to remove the part of insulating layer 1 not covered with the resist pattern, whereby the cavity 2 is formed as shown in FIGS. 2(A) and (B). The (very narrow groove part 3 of the) cavity 2 formed at that time determines the track width of the thin-film magnetic head.

Next, as shown in FIG. 7(A), a coating 16 made of Ta, W, TiN, or the like is formed on the whole surface of the insulating layer 1 by a thickness of about 200 to 500 Å by CVD or sputtering. Also, by sputtering or IBD, a coating to become a seed layer for plating with a magnetic material which will be performed later is formed on the coating 16 so as to fill the cavity 2. Subsequently, after a photoresist is applied onto the whole surface of the insulating layer 1, patterning is performed with a predetermined photomask, so as to yield a resist pattern 25 which covers substantially the whole area of the variable width depression 4 of the cavity 2, the fixed width depression 5, and surrounding parts thereof while exposing the other part of the coating 16, in order to form a magnetic layer 26, which will be explained later, at a position to form a magnetic pole end part 11.

Then, using CoNiFe having a high saturated magnetic flux density of 2.3 T to 2.4 T as a magnetic material, plating is performed with the resist pattern 25 acting as a mask. As a result, the magnetic layer 26 is formed in the part not covered with the resist pattern 25. This magnetic layer 26 will later form the magnetic pole end part 11. The magnetic layer 26 is formed by plating in the area to form the magnetic pole end part 11.

Next, the resist pattern 25 is removed, whereby a state in which the magnetic layer 26 is left in the regions not covered with the resist pattern 25 in the insulating layer 1 (the region for forming the magnetic pole end part 11 and the protruded depression 6 in the cavity 2 and surrounding regions of the cavity 2) is obtained as shown in FIGS. 8(A) and (C). Here, the magnetic layer 26 includes an in-depression inner end face 26 a (see FIG. 8(A)) exposed into a region other than the very narrow groove part 3 in the cavity 2, and acts as the end-face-equipped magnetic pole layer in the present invention. In this case, the length of the in-depression inner end face 26 a can be changed by adjusting the position at which the resist pattern 25 is formed. As the in-depression inner end face 26 a is made longer, the size of the in-depression inner end face 26 a becomes greater, whereby the connection with a magnetic layer 27 which will be explained later becomes more reliable. However, the interface 14 is distanced farther from the ABS 30, so that the quantity of magnetization in the yoke magnetic pole layer 20 becomes smaller, whereby the pole erasure is more likely to occur. In order for the pole erasure to become harder to occur, it will be sufficient if the in-depression inner end face 26 a is made shorter, although this will make the connection with the magnetic layer 27 more difficult. In view of these points, the position at which the resist pattern 25 is formed is adjusted.

Subsequently, as shown in FIGS. 9(A) and (C), the magnetic layer 27 having a thickness on the order of 0.5 to 0.8 μm is formed by sputtering using CoFe having a saturated magnetic flux density lower than that of the magnetic layer 26 or CoNiFe having a saturated magnetic flux density of 1.9 to 2.1 T with lower magnetostriction λ and maximum coercivity Hc as a magnetic material on the whole surface of the insulating layer 1 including the position where the yoke magnetic pole part 20 is to be formed. Namely, the magnetic layer 27 is formed by sputtering in a region for forming the yoke magnetic pole part 20, which is wide than the magnetic pole end part 11.

When the magnetic layer 27 is formed, the magnetic layer 27 is joined to the in-depression inner end face 26 a of the magnetic layer 26, whereby their junction forms an interface 28. Namely, the magnetic layer 27 is the joining magnetic pole layer in the present invention. The magnetic layer 27 will later form the yoke magnetic pole part 20. The interface 28 will later become the interface 14. Further, an insulating layer 29 made of alumina (Al₂O₃) is formed by a thickness on the order of 0.5 to 1.0 μm on the outside of the insulating layer 1 in the whole surface of the substrate. (The insulating layer 29 is not shown in FIG. 9(A).)

Subsequently, as shown in FIGS. 10(A) and (C), the whole surface of the substrate including the surface of the magnetic layers 26 and 27 on the side closer to the thin-film coil 100 is subjected to chemical mechanical polishing (hereinafter referred to as “CMP”) as a surface-flattening process. Here, the coating 16 made of Ta, W, TiN, or the like functions as a stopper, so that the height h1 from the bottom face of the insulating layer 1 to the surface of the magnetic layer 27 is regulated such that the depth d1 of the cavity 2 (see FIG. 3(C)) is on the order of 0.2 to 0.25 μm. Flattening this surface will later form the magnetic pole end part 11 and yoke magnetic pole part 20.

Removing the coating 16 by a method such as CMP, IBE, or RIE forms the magnetic pole end part 11 and yoke magnetic pole part 20 as shown in FIG. 11(A) and (C). Here, respective end faces of the magnetic pole end part 11 and yoke magnetic pole part extending along the ABS 30 are joined to each other in the region (variable width depression 4) other than the very narrow groove part 3 in the cavity 2. This forms a main magnetic pole layer 10 embedded in the cavity 2. A recording gap layer 24, a thin-film coil 100, a write shield layer 40, a back magnetic pole layer 51, and the like will now be formed in succession.

Then, as shown in FIGS. 12(A) and (B), a coating 34 for forming the recording gap layer 24 is formed by a thickness of 400 to 500 Å so as to cover the whole upper face of the substrate including the magnetic pole end part 11 and yoke magnetic pole part 20. The material of the coating 34 may be either an insulating material such as alumina or a nonmagnetic metal material such as Ru, NiCu, Ta, W, Cr, Al₂O₃, Si₂O₃, or NiPd. The coating 34 will later form the recording gap layer 24.

Subsequently, while opening the coating 34 in areas where a first shield part 41 and the back magnetic pole layer 51 are to be formed, the first shield part 41 and the back magnetic pole layer 51 are formed as shown in FIGS. 13(A) and (B). In this case, the first shield part 41 is formed so as to oppose the magnetic pole end part 11 by way of the recording gap layer 24 in order to determine the neck height NH. The back magnetic pole layer 51 is formed so as to join with the yoke magnetic pole part 20 at a position not covered with the recording gap layer 24. It will be sufficient if the first shield part 41 and the back magnetic pole layer 51 are formed by plating with CoNiFe or NiFe as a magnetic material as with the yoke magnetic pole part 20.

Next, the insulating layer 31 made of alumina (Al₂O₃) is formed by a thickness of 1.0 to 1.5 μm, for example, so as to cover the whole upper face of the substrate. In order for the first shield part 41 and the yoke magnetic pole part 20 to have a thickness on the order of 0.5 to 1.0 μm, their surface is subjected to CMP as a surface-flattening process. This forms an opening in a place where a second shield part 42 is to be formed.

Subsequently, as shown in FIGS. 14(A) and (B), an electrode film (not depicted) made of a conductive material and a frame made by photolithography are formed on the insulating layer 31, and then electroplating is performed with the electrode film, so as to form a plating layer made of Cu. This plating layer and the electrode film thereunder become a thin-film coil 100. The thin-film coil 100 is formed on the yoke magnetic pole part 20 by way of the insulating layer 31.

Next, though not depicted, a frame is formed by photolithography, and the second shield part 42 is formed by frame plating. The second shield part 42 uses the same magnetic material as with the first shield part 41. The second shield part 42 and the thin-film coil 100 may be formed in reverse order as well.

Subsequently, as shown in FIGS. 15(A) and (B), a photoresist 101 is applied so as to cover the whole upper face of the substrate. Further, an insulating layer 35 made of alumina (Al₂O₃) is formed by a thickness of about 3.0 to 4.0 μm thereon, and then the whole surface is subjected to CMP as a surface-flattening process.

Subsequently, as shown in FIGS. 1(A) and (B), an insulating layer made of alumina (Al₂O₃) is formed by a thickness of about 0.2 μm so as to cover the whole upper face of the substrate, and an opening is formed in the place where the second shield part 42 is formed. This yields an insulating layer 32 which insulates the thin-film coil 100 and a third shield part 43 from each other so as to prevent them from short-circuiting.

Next, the third shield part 43 is formed by a thickness of about 2 to 3 μm, whereby the write shield layer 40 is formed. The foregoing steps yield the thin-film magnetic head structure 300 shown in FIGS. 1(A) and (B). Thus obtained thin-film magnetic head structure 300 has the above-mentioned configuration, thereby being capable of effectively preventing the pole erasure from occurring, while improving the recording density. When the thin-film magnetic head structure 300 is cut at the ABS 30, a thin-film magnetic head in accordance with the present invention is obtained. This thin-film magnetic head exhibits the same operations and effects as with the thin-film magnetic head structure 300.

MODIFIED EXAMPLE 1

The manufacturing process mentioned above can be modified as follows. Namely, after the whole upper face of the semiconductor wafer is subjected to CMP as shown in FIGS. 13(A) and (B), the thin-film coil 100 is formed by way of the insulating layer 31 earlier than the second shield part 42. Subsequently, the photoresist 101 is formed so as to cover the thin-film coil 100. Further, the second shield part 42 is formed so as to cover the thin-film coil 100 and the photoresist 101, and connect with the first shield part 41 and the back magnetic pole layer 51. This yields a thin-film magnetic head structure 301 comprising the first shield part 41 and second shield part 42 without the third shield part 43 as shown in FIGS. 19(A) and (B).

This thin-film magnetic head structure 301 has the same configuration as with the thin-film magnetic head structure 300 except that it lacks the third shield part 43 and the insulating layer 32. Therefore, the thin-film magnetic head structure 301 exhibits the same operations and effects as with the thin-film magnetic head structure 300. The manufacturing process in this modified example requires no step for manufacturing the third shield part 43, and thus can become simpler than the manufacturing process of the thin-film magnetic head structure 300.

MODIFIED EXAMPLE 2

The thin-film magnetic head structure 300 can also be made without using the cavity 2. First, in this case, an end-face-equipped magnetic pole layer having an exposed end face as with the in-depression end face 16 a is formed at a position where the magnetic pole end part 11 is to be formed in the insulating layer 1. Next, at a position where the yoke magnetic pole part 20 is to be formed in the insulating layer 1, a joining magnetic pole layer joined to the exposed end face of the end-face-equipped magnetic pole layer is formed. The subsequent steps are performed as mentioned above. The manufacturing method in accordance with Modified Example 2 can yield a thin-film magnetic head structure 302 without the cavity 2.

Second Embodiment

With reference to FIGS. 16(A) and (B), the thin-film magnetic head structure in accordance with the second embodiment of the present invention will be explained. FIG. 16 is a sectional view of the thin-film magnetic head structure 310 in accordance with the second embodiment of the present invention, in which (A) is a sectional view taken along a direction intersecting a thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS.

Configuration of Thin-Film Magnetic Head Structure

The thin-film magnetic head structure 310 in accordance with the second embodiment is the same as the above-mentioned thin-film magnetic head structure 300 except that it includes a nonmagnetic film 61. The following explanation relates to their difference while omitting or simplifying descriptions concerning their common points.

The nonmagnetic film 61 is formed in a portion of the yoke magnetic pole part 20 other than its surface on the thin-film coil 100 side. Namely, the nonmagnetic film 61 is disposed at the interface 14 between the magnetic pole end part 11 and the yoke magnetic pole part 20, and in the part between the yoke magnetic pole part 20 and the coating 16. The nonmagnetic film 61 is made of Ru, Ta, W, Cr, or the like and has a thickness of about 10 to 30 Å. The nonmagnetic film 61 functions to control the direction of remnant magnetization mr in the magnetic pole end part 11 and yoke magnetic pole part 20 and prevent the direction of remnant magnetization mr from being oriented in a different direction. Therefore, the thin-film magnetic head structure 310 can more effectively prevent the pole erasure from occurring, while improving the recording density more than the thin-film magnetic head structure 300 does. The thin-film magnetic head structure 302 using no cavity 2 can also be provided with the nonmagnetic film 61.

Method of Manufacturing Thin-Film Magnetic Head Structure

The method of manufacturing the thin-film magnetic head structure 310 is the same as the method of manufacturing the thin-film magnetic head structure 300 except for the steps after forming the magnetic layer 26.

When manufacturing the thin-film magnetic head structure 310, the nonmagnetic film 61 is formed before forming the magnetic layer 27 after forming the magnetic layer 26. In this case, the nonmagnetic film 61 is formed so as to cover the in-depression inner end face 26 a and the surface within the cavity 2.

Next, the magnetic layer 27 is formed as in the thin-film magnetic head structure 300 in the first embodiment. Then, since the nonmagnetic film 61 is formed in the portion of the yoke magnetic pole part 20 other than the surface on the thin-film coil 100 side, the exposed in-depression inner face 26 a of the magnetic layer 26 and the magnetic layer 27 join with each other by way of the nonmagnetic film 61 within the cavity 2, whereby the nonmagnetic film 61 is disposed at the interface 28.

Subsequently, as in the thin-film magnetic head structure 300, an insulating layer 29 (not depicted) is formed, and the whole surface of the substrate is subjected to CMP as a surface-flattening process. This yields a state shown in FIGS. 18(A) and (B). This state corresponds to FIGS. 10(B) and (D). The subsequent steps are carried out as in the thin-film magnetic head structure 300 in the first embodiment, whereby the thin-film magnetic head structure 310 is obtained.

MODIFIED EXAMPLE 1

The manufacturing process mentioned above can be modified as in the first embodiment. Namely, after forming the first shield part 41 and the back magnetic pole layer 51, the whole upper face of the substrate is subjected to CMP, and then the thin-film coil 100 is formed by way of the insulating layer 31 earlier than the second shield part 42. Next, the photoresist 101 is formed so as to cover the thin-film coil 100. Further, the second shield part 42 is formed so as to cover the thin-film coil 100 and the photoresist 101, and connect with the first shield part 41 and the back magnetic pole layer 51. This yields a thin-film magnetic head structure 311 including a write shield layer 40 comprising the first shield part 41 and second shield part 42 without the third shield part 43 as shown in FIGS. 20(A) and (B).

This thin-film magnetic head structure 311 has the same configuration as with the thin-film magnetic head structure 310 except that it lacks the third shield part 43 and the insulating layer 32, and exhibits the same operations and effects as with the thin-film magnetic head structure 310. The manufacturing process in this modified example requires no step for manufacturing the third shield part 43, and thus can become simpler than the manufacturing process of the thin-film magnetic head structure 310.

MODIFIED EXAMPLE 2

As with the thin-film magnetic head structure 300 in accordance with the first embodiment, the thin-film magnetic head structure 310 can also be manufactured without the cavity 2. The manufacturing method in this case is as follows. First, a nonmagnetic film similar to the nonmagnetic film 61 is formed at the exposed end face of the end-face-equipped magnetic pole layer in Modified Example 2 of the first embodiment. Next, a joining magnetic pole layer joined to the exposed end face of the end-face-equipped magnetic pole layer is formed at a position where the yoke magnetic pole part 20 is to be formed in the insulating layer. This joins the end-face-equipped magnetic pole layer and the joining magnetic pole layer to each other by way of the nonmagnetic film. The other steps are performed as in Modified Example 2 of the first embodiment.

Third Embodiment

With reference to FIGS. 21(A) and (B), the thin-film magnetic head structure in accordance with the third embodiment will be explained. FIG. 21 is a sectional view of the thin-film magnetic head structure 320 in accordance with the third embodiment, in which (A) is a sectional view taken along a direction intersecting the thin-film coil, and (B) is a sectional view showing the ABS when cut at the ABS.

The thin-film magnetic head structure 320 in accordance with the third embodiment is the same as the above-mentioned thin-film magnetic head structure 300 except that it includes an upper yoke magnetic pole part 45, that it lacks the back magnetic pole layer 51, that the recording gap layer 24 and insulating layer 31 have different forms, and that it includes an insulating layer 33. The following explanation relates to their difference while omitting or simplifying descriptions concerning their common points.

The thin-film magnetic head structure 320 includes the upper yoke magnetic pole part 45, which is joined to the surface of the yoke magnetic pole part 20 on the side closer to the thin-film coil 100 at a position distant from the ABS 30 than the recording gap layer 24. The upper yoke magnetic pole part 45 is formed together with the first shield part 41 when the first shield part 41 is formed by plating.

Joining the upper yoke magnetic pole part 45 to the yoke magnetic pole part 20 can increase the quantity of magnetization of the main magnetic pole layer 10 in the vicinity of the ABS 30. Therefore, the thin-film magnetic head structure 320 can manufacture a thin-film magnetic head having a favorable overwrite characteristic.

When manufacturing the thin-film magnetic head structure 320, it will be sufficient if a step of joining the upper yoke magnetic pole part 45 to a part distant from the ABS 30 than the recording gap layer 24 in the yoke magnetic pole part 20 is provided. In this case, the thin-film magnetic head structure 320 can be manufactured either with or without the cavity 2.

As with the thin-film magnetic head structure 300 in accordance with the first embodiment, the thin-film magnetic head structure 320 can be made as a thin-film magnetic head structure 321 shown in FIGS. 22(A) and (B). This thin-film magnetic head structure 321 includes a write shield layer 40 comprising the first shield part 41 and second shield part 42 without the third shield part 43.

Though not depicted, the nonmagnetic film 61 may be formed in the portion where the magnetic pole end part 11 and the yoke magnetic pole part 20 are joined to each other and in the portion between the yoke magnetic pole part 20 and the coating 16 in any of the thin-film magnetic head structures 320 and 321.

It is apparent that various embodiments and modifications of the present invention can be embodied, based on the above description. Accordingly, it is possible to carry out the present invention in the other modes than the above best mode, within the following scope of claims and the scope of equivalents. 

1. A thin-film magnetic head structure adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated; wherein the main magnetic pole layer has an end face joint structure where respective end faces of the magnetic pole end part and a yoke magnetic pole part having a size greater than that of the magnetic pole end part are joined to each other, and a surface with a flat structure on a side closer to the thin-film coil.
 2. A thin-film magnetic head structure according to claim 1, further comprising a base insulating layer including a magnetic pole forming depression sunken into a form corresponding to the main magnetic pole layer, the magnetic pole forming depression having a very narrow groove part formed so as to define a track width of the thin-film magnetic head; wherein the respective end faces of the magnetic pole end part and yoke magnetic pole part are joined to each other within a region other than the very narrow groove part in the magnetic pole forming depression of the base insulating layer.
 3. A thin-film magnetic head structure according to claim 1, wherein the magnetic pole end part and the yoke magnetic pole part are formed from respective magnetic materials having saturated magnetic flux densities different from each other.
 4. A thin-film magnetic head structure according to claim 2, wherein the magnetic pole end part and the yoke magnetic pole part are formed from respective magnetic materials having saturated magnetic flux densities different from each other.
 5. A thin-film magnetic head structure according to claim 3, wherein the saturated magnetic flux density of the magnetic pole end part is set higher than the saturated magnetic flux density of the yoke magnetic pole part.
 6. A thin-film magnetic head structure according to claim 4, wherein the saturated magnetic flux density of the magnetic pole end part is set higher than the saturated magnetic flux density of the yoke magnetic pole part.
 7. A thin-film magnetic head structure according to claim 1, wherein the magnetic pole end part and the yoke magnetic pole part are joined to each other by way of a nonmagnetic film made of a nonmagnetic material.
 8. A thin-film magnetic head structure according to claim 2, wherein the magnetic pole end part and the yoke magnetic pole part are joined to each other by way of a nonmagnetic film made of a nonmagnetic material.
 9. A thin-film magnetic head structure according to claim 1, wherein an upper yoke magnetic pole part having a size greater than that of the magnetic pole end part is joined to a portion of the yoke magnetic pole part distant from the medium-opposing surface than the recording gap layer.
 10. A thin-film magnetic head structure according to claim 2, wherein an upper yoke magnetic pole part having a size greater than that of the magnetic pole end part is joined to a portion of the yoke magnetic pole part distant from the medium-opposing surface than is the recording gap layer.
 11. A thin-film magnetic head structure according to claim 1, wherein the very narrow groove part is formed such that a groove width intersecting the length thereof gradually decreases along the depth thereof.
 12. A thin-film magnetic head structure according to claim 2, wherein the very narrow groove part is formed such that a groove width intersecting the length thereof gradually decreases along the depth thereof.
 13. A method of manufacturing a thin-film magnetic head structure adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated; the method comprising the steps of: forming an end-face-equipped magnetic pole layer having an exposed end face at a position where the magnetic pole end part is to be formed; forming a joining magnetic pole layer joined to the exposed end face of the end-face-equipped magnetic pole layer at a position where a yoke magnetic pole part having a size greater than that of the magnetic pole end part is to be formed; surface-flattening the end-face-equipped magnetic pole layer and joining magnetic pole layer on the side closer to the thin-film coil, so as to form the magnetic pole end part and the yoke magnetic pole part having a size greater than that of the magnetic pole end part; forming the recording gap layer with the magnetic pole end part and the yoke magnetic pole part; forming the thin-film coil with the yoke magnetic pole part such that the thin-film coil and the yoke magnetic pole part are in contact with each other by way of an insulating layer; and forming the write shield layer such that the write shield layer opposes the magnetic pole end part by way of the recording gap layer.
 14. A method of manufacturing a thin-film magnetic head structure adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated; the method comprising the steps of: forming a base insulating layer including a magnetic pole forming depression sunken into a form corresponding to the main magnetic pole layer, the magnetic pole forming depression having a very narrow groove part formed so as to define a track width of the thin-film magnetic head; forming an end-face-equipped magnetic pole layer having an in-depression end face exposed into a region other than the very narrow groove part in the magnetic pole forming depression of the base insulating layer; forming a joining magnetic pole layer joined to the in-depression end face in the end-face-equipped magnetic pole layer; surface-flattening the end-face-equipped magnetic pole layer and joining magnetic pole layer on the side closer to the thin-film coil, so as to form the magnetic pole end part and the yoke magnetic pole part having a size greater than that of the magnetic pole end part; forming the recording gap layer with the magnetic pole end part and the yoke magnetic pole part; forming the thin-film coil with the yoke magnetic pole part such that the thin-film coil and the yoke magnetic pole part are in contact with each other by way of an insulating layer; and forming the write shield layer such that the write shield layer opposes the magnetic pole end part by way of the recording gap layer.
 15. A method of manufacturing a thin-film magnetic head structure according to claim 13, further comprising the step of forming a nonmagnetic film made of a nonmagnetic material at the exposed end face in the end-face-equipped magnetic pole layer; wherein the joining magnetic pole layer is formed so as to join with the end-face-equipped magnetic pole layer by way of the nonmagnetic film.
 16. A method of manufacturing a thin-film magnetic head structure according to claim 14, further comprising the step of forming a nonmagnetic film made of a nonmagnetic material at the in-depression end face in the end-face-equipped magnetic pole layer; wherein the joining magnetic pole layer is formed so as to join with the end-face-equipped magnetic pole layer by way of the nonmagnetic film.
 17. A method of manufacturing a thin-film magnetic head structure according to claim 13, further comprising the step of joining an upper yoke magnetic pole part having a size greater than that of the magnetic pole end part to a portion of the yoke magnetic pole part distant from the medium-opposing surface than the recording gap layer.
 18. A method of manufacturing a thin-film magnetic head structure according to claim 14, further comprising the step of joining an upper yoke magnetic pole part having a size greater than that of the magnetic pole end part to a portion of the yoke magnetic pole part distant from the medium-opposing surface than the recording gap layer.
 19. A thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated; the thin-film magnetic head comprising: a base insulating layer including a magnetic pole forming depression sunken into a form corresponding to the main magnetic pole layer, the magnetic pole forming depression having a very narrow groove part formed so as to define a track width of the thin-film magnetic head; wherein the main magnetic pole layer has an end face joint structure where respective end faces of the magnetic pole end part and a yoke magnetic pole part having a size greater than that of the magnetic pole end part are joined to each other, and a surface with a flat structure on a side closer to the thin-film coil. 